add code for creating ingredients [expect to pass]

app/recipe/serializers.py

@@ -31,10 +31,12 @@ class Meta:
 class RecipeSerializer(serializers.ModelSerializer):
     """Serializer for recipes."""
     tags = TagSerializer(many=True, required=False)
+    ingredients = IngredientSerializer(many=True, required=False)
 
     class Meta:
         model = Recipe
-        fields = ['id', 'title', 'time_minutes', 'price', 'link', 'tags']
+        fields = ['id', 'title', 'time_minutes',
+                  'price', 'link', 'tags', 'ingredients',]
         read_only_fields = ['id']
 
     def _get_or_create_tags(self, tags, recipe):
@@ -48,11 +50,23 @@ def _get_or_create_tags(self, tags, recipe):
             )
             recipe.tags.add(tag_obj)
 
+    def _get_or_create_ingredients(self, ingredients, recipe):
+        """Handle getting or creating ingredients as needed."""
+        auth_user = self.context['request'].user
+        for ingredient in ingredients:
+            ingredient_obj, created = Ingredient.objects.get_or_create(
+                user=auth_user,
+                **ingredient,
+            )
+            recipe.ingredients.add(ingredient_obj)
+
     def create(self, validated_data):
         """Create a recipe."""
         tags = validated_data.pop('tags', [])
+        ingredients = validated_data.pop('ingredients', [])
         recipe = Recipe.objects.create(**validated_data)
         self._get_or_create_tags(tags, recipe)
+        self._get_or_create_ingredients(ingredients, recipe)
 
         return recipe